// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef NET_TOOLS_BALSA_SIMPLE_BUFFER_H__
#define NET_TOOLS_BALSA_SIMPLE_BUFFER_H__

#include <string>

#include "base/compiler_specific.h"
#include "base/macros.h"
#include "net/tools/balsa/buffer_interface.h"

namespace net {

class SimpleBuffer : public BufferInterface {
public:
    SimpleBuffer();
    explicit SimpleBuffer(int size);
    ~SimpleBuffer() override;

    std::string str() const;

    typedef char* iterator;
    typedef const char* const_iterator;

    iterator begin() { return storage_ + read_idx_; }
    const_iterator begin() const { return storage_ + read_idx_; }

    iterator end() { return storage_ + write_idx_; }
    const_iterator end() const { return storage_ + write_idx_; }

    // The following functions all override pure virtual functions
    // in BufferInterface. See buffer_interface.h for a description
    // of what they do.
    int ReadableBytes() const override;
    int BufferSize() const override;
    int BytesFree() const override;

    bool Empty() const override;
    bool Full() const override;

    int Write(const char* bytes, int size) override;

    void GetWritablePtr(char** ptr, int* size) const override;

    void GetReadablePtr(char** ptr, int* size) const override;

    int Read(char* bytes, int size) override;

    void Clear() override;

    // This can be an expensive operation: costing a new/delete, and copying of
    // all existing data. Even if the existing buffer does not need to be
    // resized, unread data may still need to be non-destructively copied to
    // consolidate fragmented free space.
    bool Reserve(int size) override;

    void AdvanceReadablePtr(int amount_to_advance) override;

    void AdvanceWritablePtr(int amount_to_advance) override;

    void Swap(SimpleBuffer* other)
    {
        char* tmp = storage_;
        storage_ = other->storage_;
        other->storage_ = tmp;

        int tmp_int = write_idx_;
        write_idx_ = other->write_idx_;
        other->write_idx_ = tmp_int;

        tmp_int = read_idx_;
        read_idx_ = other->read_idx_;
        other->read_idx_ = tmp_int;

        tmp_int = storage_size_;
        storage_size_ = other->storage_size_;
        other->storage_size_ = tmp_int;
    }

protected:
    char* storage_;
    int write_idx_;
    int read_idx_;
    int storage_size_;

private:
    //DISALLOW_COPY_AND_ASSIGN(SimpleBuffer);
};

} // namespace net

#endif // NET_TOOLS_BALSA_SIMPLE_BUFFER_H__
